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> > Baetis v Empheralla Attenuata

ByhaughDecember 16th, 2013, 7:56 pm

Posts: 56
I am new here.
I have a question. I know there is (or may be) a difference between an Eastern Blue Winged Olive and a Western Blue Winged Olive?

My question is this. I have always heard the Blue Winged Olive referred to as a Baetis - both in the Midwest and out West.
I am looking at the little publications "Compara-hatch" by Caucci and Nastasi. In the little stream side identification phamplet, they identify the Ephemerella Attenuata as the Blue-Winged Olive.
I think their work was done primarily on Eastern rivers. At what geographic location does the Blue Winged Olive change from Ephemerella Attenuata to Baetis while, all the while, retaining its common name as a Blue-Winged Olive?

TaxonDecember 16th, 2013, 11:25 pm
Site Editor
Royse City, TX

Posts: 1350
Hi Byron-

Welcome to When someone asks a question involving both mayfly common names and mayfly taxononic names, it is often impossible to answer that question with much precision. However, I will do my best.

As you say, Blue-Winged Olive is a mayfly common name, which is used by fly fishers to refer to numerous genera and species of family Baetidae (Small Minnow Mayfly), at least one of which is found nearly every USA state.

Conversely, Blue-Winged Olive is also a mayfly common name used by fly fishers to refer to several genera and species of family Ephemerellidae (Spiny Crawler Mayfly) primarily found in the eastern USA states.

Hope this helps.
Best regards,
Roger Rohrbeck
CrepuscularDecember 16th, 2013, 11:47 pm
Boiling Springs, PA

Posts: 923
Hi Byron. Welcome to TN. This topic comes up pretty often. I like to think of common names for mayflies as the general name of the fly pattern (Parachute BWO or BWO Spinner) and the taxonomic name as the name of the insect.
Like Rodger said, there are some mayfly species from both the Baetis and other Baetidae genera and the family Ephemerellidae that are called blue-winged olives whenever and wherever they are found. For some more info this check this out
So really geography does not play a role other than in one area of North America, a particular mayfly species may have a common name that is different than the common name of the same mayfly in a different area of the continent. Or a mayfly of a single species may not exist all parts of North America but yet have the same common name as a completely different species that occurs in a separate geographical area.
And if you want to add to the confusion, Ephemerella attenuata is no longer a valid taxonomic name. It is now Attenella attenuata.
OldredbarnDecember 17th, 2013, 5:04 pm
Novi, MI

Posts: 2608
Clear as mud, boys! ;)

"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
CrepuscularDecember 17th, 2013, 6:50 pm
Boiling Springs, PA

Posts: 923
Clear as mud, boys! ;)


I know. Why don't you clear it up for us. ;) I should've let this one go. Rodger did just fine without me mucking it up
EntomanDecember 18th, 2013, 4:09 am
Northern CA & ID

Posts: 2604
Welcome, Byron!

You are pretty spot on regarding the use (or rather misuse) of the name regionally.

The name has its origins in English FF literature going back to antiquity and has been universally adopted over there as the common one for their only green bodied species of ephemerellid. They use it to describe no other mayfly species. When an English angler mentions to another that "the Blue-winged Olives were coming off" they both know EXACTLY the insect in question. Simple and nonconfusing. Unfortunately, the sheer size and scope of the diversity in our fauna precludes such tidiness. The gray winged olive bodied color scheme is by far the most common in the order with examples being found in almost every family here in North America. Species that can be called Blue-winged Olive (and indeed have been) are legion. Though mostly applied improperly in the West it has been misused back East as well.

More humor can be found on this topic than almost any other in our archives. In an attempt to resolve the confusion, Gonzo came up with the idea of calling eastern ephemerellids with green bodies the lyrical name "Morning Olive Duns." My thoughts were that regardless of geography, only olive ephemerellids should be rightly called BWO's (respecting our literary heritage going back hundreds of years) and olive baetids should be called "Olive Quills." Alas, too simple and orderly for our community to ever adopt in practice. :)
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman

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